There has been known an image forming apparatus having APS (Auto Paper Select) function which automatically selects a recording medium from paper feeding cassette based on a document size and magnification and conveys to improve user-friendliness for users.
The Patent Document 1 discloses an image forming apparatus having APS function wherein in case media in feeding cassette are used up while forming an image, if a cassette storing the same size recording medium having the same direction does not exist and if a cassette storing the same size recording medium having a different direction exists, image forming is continued by turning around the image by 90 degree to form the image on the same size recording medium having the different direction.
[Patent Document 1] Official Gazette of Japanese Patent Tokkaihei 7-129043
In recent years, a number of image forming apparatus capable of being connected with post process apparatuses having folding function are on the market.
In such image forming apparatus, if APS function and folding function are simultaneously used, APS function may accidentally select a recording medium which cannot be folded by the APS function. Thus, image forming is discontinued.
For example, in case tri-folding is designated for A4-longitudinal (longitudinal means a short side of the recording medium is parallel to a medium conveying direction) document, usually, tri-folding is not likely to be executed for A4 recording medium, execution of tri-folding is made impossible. A4 longitudinal recoding medium has a mechanical difficulty in folding, since A4 longitudinal orientation recoding medium is short in the conveying direction compared to A4 lateral recording medium.
The technology in Patent Document 1 is a technology which enables to continue image forming when the sheet in use is used up however, it does not consider folding in continuation of the image forming.